Joint replacement surgery is quite common and it enables many individuals to function properly when they otherwise would not be possible to do so. Such patients of joint replacement surgery typically suffer from osteoarthritis or rheumatoid arthritis. Artificial joints usually comprise metallic, ceramic and/or plastic components that are fixed to existing bone.
Such joint replacement surgery is otherwise known as total joint arthroplasty. Total joint arthroplasty is a well-known surgical procedure by which a diseased and/or damaged joint is replaced with a prosthetic joint. In a typical total joint arthroplasty, the ends or distal portions of the bone adjacent the joint are resected or a portion of the distal part of the bone is removed and the artificial joint is secured thereto.
For many patients suffering from osteoarthritis or rheumatoid arthritis, the procedure of total joint arthroplasty results in a prosthetic joint, which serves the patient through his or her entire life. Unfortunately, for a variety of reasons, some patients having total joint arthroplasty are not as fortunate, and the prosthetic joint must be replaced. Such a procedure to replace a prosthetic joint with a replacement prosthetic joint is called revision total joint arthroplasty. For such replacement surgery, the original or primary implant must be removed from the body or severed from the bone.
Proper implantation of an implant during total joint arthroplasty frequently suggests that the joint be firmly secured to the adjoining bone. For example, when utilizing bone cement to secure the original prosthetic joint, pressure is applied when utilizing the cement to cause the cement to interdigitate or move somewhat in to the cancellous bone around the joint.
Alternatively, when a prosthetic joint is utilized without bone cement, often the prosthetic joint includes an outer porous coating, which provides over time for bony ingrowth within the porous portion of the prosthesis. Whether the implant is secured with interdigitated cement or bony ingrowth, the removal of the prosthesis from the bone may be quite difficult. Typically, to remove the prosthesis, tools, for example, in the form of hand tools such as Moreland instruments or Dremel type-cutting instruments are used.
These cutting instruments are utilized by the surgeon in a free hand procedure in which the tools are manually moved near the periphery of the prosthesis until the prosthesis and the bone are separated from each other.
Since this procedure is done manually and freehand with no additional tools to assist in the placement and movement of the hand tools around the bone, the result is often that excess bone is removed from the implant. Generally, good surgical procedure requires and suggests that only the minimal amount of bone be removed from the patient. Furthermore, to implant replacement prosthesis, bone must remain to secure the replacement prosthesis to the bone.
A need does exist for improved method and instrumentation to assist in the removal of a joint implant which provides for more accurate placement of the tools during the cutting procedure, and that provides for a procedure that also may be less time consuming than the current manual freehand approach.